Organic light-emitting devices, such as, for example, organic light-emitting diodes (OLEDs), conventionally contain fluorescent or phosphorescent emitter materials. The organic molecules used for this purpose generally have a wide, defined emission spectrum which, without using additional, external converters, cannot be shifted into the high- or low-energy range of the visible spectrum. Achieving low-energy, i.e. dark red, emission is moreover difficult since the quantum efficiency of the emitter materials increases sharply with increasing wavelength due to an exponential increase in the non-radiative rate.
For example, red emitting materials with a dominant wavelength of at most 610 to 615 nm are used in today's OLEDs. Currently, the only option for shifting this dominant wavelength towards larger wavelengths involves using converter materials which are applied externally onto the OLED. This disadvantageously has a negative impact on the appearance and thus the shape and design advantage of OLEDs and color conversion moreover generally results in a severe reduction in efficiency.